Brush-holder.



N. c. BASSETT. BRUSH HOLDER. APPLIOATION IILED'MAR.24,1902.

Patented Aug. 10, 1909.

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' N G. B ASSETT.

BRUSH HOLDER.

APPLICATION FILLED MAB.241902.

nn W E m no t m mfi Mn nC w vn m no P O N w UNITED STATES PATENT onnren.

NORMAN C. BASSETT, OF LYNN, MASSACHUSETTS, AS SIGNOR TO GENERAL ELECTRICCOMPANY, A CORPORATIOY OF NEW YORK.

BRUSH-HOLDER.

Application filed March 24, 1902.

To all whom it may concern:

Be it known that I, NORMAN C. Bnssnrr, a citizen of the United States,residin at Lynn, county of Essezgstate of Massachusetts, have inventedcertain new and useful Improvements in Brush-IIolclers, of which thefollowing is a specification.

This invention relates to brush-holders for dynamo-electric machines,and its object is to provide a device of this character in which thebrush is supported by two surfaces on opposite sides of the same but notoppositeeach other. In brush-holders where the brush is supportedagainst a rather broad flat surface, it is frequently the case that theyare in contact at only a few points, owing to the brush being warped oruneven. This renders it liable to rock and chatter, and the purpose ofmy invention is to avoid this by the special construction adopted.Across the brush holder and near the commutator is a comparativelynarrow strip of surface against which the lower end of the brush rests,while on the opposite side of the brush and near its upper end, is asimilar narrow strip of supporting surface, preferably smaller than thelower one. This mode of supporting the brush prevents it from rockingand ermits the use of uneven and irregular brus ies without thenecessity of surfacing them beforehand to make them lie flat against theholder.

In the accompanying drawings, Figure l is a side elevation of abrush-holder embodying my improvements Figs. 2, 3, 4 and 5 are sideelevations, partly in section, of modified constructions of the same;Fig. 6 is a side elevation of a further modification showing a specifiedmeans for adjusting the tension of the follower-spring; Fig. 7 is a rearelevation of the same, partly broken away.

The brush-holder A is a casting of suitable shape, provided with atransverse hole a to ena le it to be secured upon a supporting stud B,preferably by means of a key B At the lower end of the holder, near thecommutator C, is a transverse fiat surface a, not very wide andpreferably inclined to the radius of the commutator. An electricconducting block D rests against this surface, near its lower end, whileits upper end is supported by a transverse surface on the opposite sideof the brush. In Figs. 1, 3 and 4 this upper surface is a flat cross-bara ,wl1ile Specification of Letters Patent.

Patented Aug. 10, 1909.

Serial No. 99,624.

in Fig. 2 and Fig. 6 it consists of a roller A loosely ournaled on atransverse pin a". In Fig. 5 a combination of the flat surface and theroller is" used.

The block is preferablymade of carbon, and its ends are inclined to thesides thereof, said ends being beveled in parallel planes, preferablyperpendicular to the radiusof the commutator. The brush can therefore beslipped into the holder either end downward, and can 'be reversed endfor end when desired.

Pivoted to the brush holder in the rear of the brush is a follower E,the free end of which rests on the upper end of the brush. A spring isprovided to cause the follower to eXert a pressure on said brush inorder to feed it downward. as it wears away and also to force it intogood electrical contact with the holder. In Fig. 1 the spring F is asimple helical spring attached at one end to the holder and at the otherend to the follower. In Figs. 2, 3, 4 and 5 the spring F is in thenature of a clock-spring coiled around a stationary pin A fixed in theholder, one end of the spring being fastened to the pin and the otherend being formed with a handle f which can be engaged with any one of aplurality of notches in a quadrant e on the follower, in order to adjustthe tension of the spring. The end of the follower may be plain as shownin Figs. 1 and 6, or provided with a friction. roller E, as in Figs. 2,3, 4 and 5.

It will be observed that the line along which the follower exerts itspressure on the brush is oblique to the longitudinal axis of the brush,so that the effect of such pressure is to force the upper part of thebrush closely against the upper supporting surface at the same time thatit feeds it downward againstthe commutator. The reaction of the commutator keeps the lower part of the brush in good contact with the lowersupporting surface.

In Figs. 6 and 7 is shown a device for adjusting the tension of ahelical followerspring. The lower end of the spring is at tached to ananchorage or abutment in the form of a block G which is fitted to slideon the back of the holder. An adjusting screw H rotates in a bearing inthe upper art of the block, and meshes with a screwthreaded hole in alug a on the holder. By turning the screw the block G will be moved upor down and the tension of the spring varied accordingly. The ends ofthe lug a serve as stops to limit the movement of the block G. The headof the screw may fit into a notch g in the upper end of the block, so asto lock it against accidental rotation when once adjusted.

This construction is very simple and easy of adjustment, and is notlikely to be shifted in the ordinary handling of the brush-hold er.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is,

1. A brush-holder having narrow surfaces for supporting a brush onopposite sides of the same but displaced with respect to each otherlengthwise of the brush, one of said surfaces being movable.

2. A brush-holder having a narrow surface for supporting the brush nearthe commutator and another narrow surface on the opposite side of thebrush displaced with re spect to said first mentioned surface lengthwiseof the brush for supporting the brush near its upper end, the lastmentioned surface being movable.

3. A brush-holder having a surface lying in front of and supporting thebrush near the commutator only, and an .antifriction support lying inthe rear of the brush near its upper end only, said surface and saidsupport being displaced with respect to each other lengthwise of thebrush.

4. A brush-holder having a narrow surface for supporting the brush nearthe commutator and a roller displaced with respect to said surfacelengthwise of the brush for supporting the brush near its upper end buton the other side thereof, in combination with a follower whose line ofpressure is obliquely downward toward the upper supporting surface.

5. A brush-holder having a narrow surface for supporting the brush nearthe commutator and another narrow surface on the opposite side of thebrush displaced with respect to said first mentioned surface lengthwiseof the brush for supporting the brush near its upper end, said surfaceshaving no supporting surfaces opposite them.

6. A brush-holder body comprising similar and parallel end piecesconnected by a narrow, angularly disposed back for the brush and anarrow supporting surface on the opposite side of said brush displacedwith re spect to said back lengthwise of the brush,

said back and said surface having no supporting surfaces opposite them.

In witness whereof I have hereunto set my hand this 20th day of March,1902.

BENJAMIN B. HULL, HELEN ORFORD.

